Hindered piperidine stabilizers and production thereof

ABSTRACT

A hindered piperidine compound represented by the formula of ##STR1## wherein R 1  is a 2,2,6,6-tetramethyl-4-piperidyl group of which the N-position is substituted or not, a hydrogen atom, a C 1  -C 18  alkyl group which may contain a cyclic portion, or a C 7  -C 18  arylalkyl group, R 2  is a hydrogen atom, a C 1  -C 10  alkyl group which may contain a cyclic portion, a C 1  -C 18  alkyloxy group which may contain a cyclic portion, or a hydroxyl group, and n is an integer of 2 to 8, effectively stabilizes organic materials having a property to deteriorate by the action of light. A method for producing the compound represented by the above formula is also disclosed.

The present invention relates to the stabilization of organic materialsby incorporating a particular hindered piperidine compound into theorganic materials, novel hindered piperidine compounds and production ofsome of the compounds.

It is known that organic materials such as various synthetic resins,including polyethylene, polypropylene, polyvinyl chloride, polyurethaneand ABS resins, natural or synthetic rubbers, paints and the likedeteriorate by the action of light, and as a result that their physicalproperties show a large reduction accompanied by phenomena such assoftening, embrittlement or discoloration. Because of this, variouslight stabilizers have so far been developed and used, but demands fornovel and more superior light stabilizers are still strong even now.Particularly, developments of light stabilizer compounds having ahindered piperidine skeleton, i.e. a 2,2,6,6-tetramethyl-4-piperidylgroup, are actively tried.

For example, EP-A-34829 discloses a compound having a2,2,6,6-tetramethyl-4-aminopiperidine skeleton and besides forming acarboxylic acid salt, particularly a nickel salt at another site.However, the nickel salt shown here is green, and such coloration of thecompound itself is a serious hindrance to use of the compound as a lightstabilizer for organic materials.

Further, the above EP-A-34829 discloses a method for producing a loweralkyl ester of the piperidine compound before forming the salt bysubjecting 4-alkylamino-2,2,6,6-tetramethylpiperidine orN,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)alkylenediamine to Michaelreaction with an acrylic acid ester. This method, however, has adrawback that the yield of the desired compound lowers when the acrylicacid ester used has a sterically bulky substituent.

The present inventors have continued a study to develop a stabilizerexhibiting excellent stabilizing effect against the deterioration oforganic materials by photo-oxidation, and as a result have found that aparticular hindered piperidine compound has excellent effect. Thepresent inventors thus attained to the present invention.

An object of the present invention is to provide a compound having suchproperties that it exhibits a high stabilizing effect against thedeterioration of organic materials by photo-oxidation, and also ititself is white to colorless, giving no color to the organic materialsto be stabilized when added thereto.

Another object of the present invention is to stabilize organicmaterials with such compound.

A further object of the present invention is to produce useful compoundsamong such compounds in good yields.

According to the present invention, there is provided a particularhindered piperidine compound used as a stabilizer for organic materials.This hindered piperidine compound is represented by the followingformula (I): ##STR2## wherein R¹ is a 2,2,6,6-tetramethyl-4-piperidylgroup of which the N-position is substituted or not, a hydrogen atom, aC₁ -C₁₈ alkyl group which may contain a cyclic portion, or a C₇ -C₁₈arylalkyl group; R² is a hydrogen atom, a C₁ -C₁₀ alkyl group which maycontain a cyclic portion, a C₁ -C₁₈ is alkyloxy group which may containa cyclic portion, or a hydroxyl group; and n is an integer of 2 to 8.

Thus, the present invention provides a method for stabilizing organicmaterials by blending them with a stabilizing amount of the hinderedpiperidine compound represented by the above formula (I), and alsoprovides stabilized organic material compositions comprising the organicmaterials and the hindered piperidine compound represented by the aboveformula (I).

The compound of the formula (I) wherein R¹ is a2,2,6,6-tetramethyl-4-piperidyl group of which the N-position issubstituted or not, a C₅ -C₁₈ alkyl group which may contain a cyclicportion or a C₇ -C₁₈ arylalkyl group is a novel compound. Thus, thepresent invention further provides a hindered piperidine compoundrepresented by the formula (I), wherein R¹ is a2,2,6,6-tetramethyl-4-piperidyl group of which the N-position issubstituted or not, a C₅ -C₁₈ alkyl group which may contain a cyclicportion, or a C₇ -C₁₈ arylalkyl group, and R² and n are as definedabove.

Further, according to the present invention, there is provided a methodfor producing the hindered piperidine compound represented by theformula (I) by transesterification, in which formula R¹ is a2,2,6,6-tetramethyl-4-piperidyl group of which the N-position issubstituted or not, a C₃ -C₁₈ alkyl group which may contain a cyclicportion, or a C₇ -C₁₈ arylalkyl group, and R² and n are as definedabove.

In the aforementioned formula (I) representing the hindered piperidinecompound which is the stabilizer component of the present invention, R¹is a 2,2,6,6-tetramethyl-4-piperidyl group of which the N-position issubstituted or not, a hydrogen atom, a C₁ -C₁₈ alkyl group which maycontain a cyclic portion, or a C₇ -C₁₈ arylalkyl group. When R¹ is a2,2,6,6-tetramethyl-4-piperidyl group, a substituent bonded to theN-position includes C₁ -C₁₀ alkyl groups which may contain a cyclicportion, C₁ -C₁₈ alkyloxy groups which may contain a cyclic portion, anda hydroxyl group. The 2,2,6,6-tetramethyl-4-piperidyl group, therefore,is generally represented by the following formula (II), ##STR3## whereinR³ is a hydrogen atom, a C₁ -C₁₀ alkyl group which may contain a cyclicportion, a C₁ -C₁₈ alkyloxy group which may contain a cyclic portion, ora hydroxyl group.

When R³ in the formula (II) is an alkyl group having 3 or more carbonatoms, the alkyl group may be of either a straight-chain form or abranched form and also may contain a cyclic portion. A preferred alkylgroup containing a cyclic portion and represented by R³ includes thosecontaining a cyclic alkyl group at the middle or terminal and bonding tothe nitrogen atom through --CH₂ --. Particularly preferred examples area cyclohexylmethyl group and a cyclohexylethyl group. Similarly, when R³in the formula (II) is an alkyloxy group having 3 or more carbon atoms,the alkyl moiety of the group may be of either a straight-chain form orbranched form and also may contain a cyclic portion. The alkyloxy groupcontaining a cyclic portion and represented by R³ may be a cyclicalkyloxy group such as cyclohexyloxy. Those which are particularlypreferred as R³ in the formula (II) include hydrogen, a C₁ -C₃ alkyl,octyloxy, cyclohexyloxy and the like.

When R¹ in the formula (I) is an alkyl group, it includes, for example,methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl,tert-butyl, n-pentyl, n-hexyl, cyclohexyl, n-octyl, 2-ethylhexyl,n-decyl, n-dodecyl, n-octadecyl and the like. Among these alkyl groups,those having 3 or more carbon atoms may be of either a straight-chainform, branched form or cyclic form. When R¹ is an arylalkyl group, itincludes, for example, benzyl, phenethyl and the like.

Among these R¹ s, preferred ones include2,2,6,6-tetramethyl-4-piperidyl, 1,2,2,6,6-pentamethyl-4-piperidyl,2,2,6,6-tetramethyl-1-octyloxy-4-piperidyl,1-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidyl,1-hydroxy-2,2,6,6-tetramethyl-4-piperidyl, hydrogen, methyl, ethyl,2-ethylhexyl and the like.

The group R² in the formula (I) is a hydrogen atom, a C₁ -C₁₀ alkylgroup which may contain a cyclic portion, a C₁ -C₁₈ alkyloxy group whichmay contain a cyclic portion, or a hydroxyl group. When R² is an alkylgroup, it may be methyl, ethyl, propyl or the like. When the alkyl grouphas 3 or more carbon atoms, it may be of either a straight-chain form orbranched form and also may contain a cyclic portion. A preferred alkylgroup containing a cyclic portion and represented by R² includes thosecontaining a cyclic alkyl group at the middle or terminal and bonding tothe nitrogen atom through --CH₂ --. Particularly preferred examples area cyclohexylmethyl group and a cyclohexylethyl group. When R² is analkyloxy group, it may be, for example, methoxy, ethoxy, hexyloxy,octyloxy or the like. Similarly, when the alkyloxy group has 3 or morecarbon atoms, its alkyl moiety may be of either a straight-chain form orbranched form and also may contain a cyclic portion. The alkyloxy groupcontaining a cyclic portion and represented by R² may be a cyclicalkyloxy group such as cyclohexyloxy. Among these R² s, preferred onesinclude hydrogen, a C₁ -C₃ alkyl, octyloxy, cyclohexyloxy and hydroxyl.

The symbol n in the formula (I) is an integer of 2 to 8, and alkylenerepresented by --C_(n) H_(2n) -- may be of either a straight-chain formor branched form. Specific examples of alkylene represented by --C_(n)H_(2n) -- include ethylene, 1,2- or 1,3-propylene, 1,2-, 1,3- or1,4-butylene, pentamethylene, hexamethylene, octamethylene and the like.Particularly preferably, n is 6, i.e. --C_(n) H_(2n) -- ishexamethylene.

Among the hindered piperidine compounds represented by the formula (I),particularly useful ones as a stabilizer are compounds in which R¹ is2,2,6,6-tetramethyl-4-piperidyl, 1,2,2,6,6-pentamethyl-4-piperidyl,2,2,6,6-tetramethyl-1-octyloxy-4-piperidyl, methyl, 2-ethylhexyl orhydrogen, R² is hydrogen, methyl, methoxy or octyloxy and n is 6. Amongthese, compounds in which R¹ is 4-piperidyl or methyl and R² is hydrogenare particularly preferred.

In the aforementioned EP-A-34829, particularly in Example 3 thereof,there is disclosed a method for producing one of the compoundsrepresented by the foregoing formula (I), i.e. a compound wherein R¹ ismethyl and R² is hydrogen, by subjectingN,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine and methylacrylate together to Michael reaction. According to the method describedabove, hindered piperidine compounds represented by the formula (I),particularly those in which R¹ is a lower alkyl group, can be produced.That is, a hindered piperidine compound represented by the formula (I)is obtained by Michael reaction of an alkylenediamine compoundrepresented by the formula (III), ##STR4## wherein R² and n are asdefined above, and an acrylic acid ester represented by the formula(IV), ##STR5## wherein R¹ is as defined above.

Specific examples of the alkylenediamine compound represented by theformula (III) include the following:

N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-ethylenediamine,

N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,4-butanediamine,

N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,8-octanediamine,

N,N'-bis(1,2,2,6,6-pentamethyl-4-piperidyl)-1,6-hexanediamine,

N,N'-bis(1-hydroxy-2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

N,N'-bis(1-methoxy-2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

N,N'-bis(2,2,6,6-tetramethyl-1-octyloxy-4-piperidyl)-1,6-hexanediamineand the like.

Specific examples of the acrylic acid ester represented by the formula(IV) include methyl acrylate, ethyl acrylate and the like. Among these,methyl acrylate is particularly preferably used.

Usually, it is preferred to carry out the reaction of thealkylenediamine compound of the formula (III) with the acrylic acidester of the formula (IV) in a solvent. The preferred solvent includesalcohols such as methanol, ethanol, isopropanol and butanol, aromatichydrocarbons such as benzene, toluene and mesitylene, chlorinatedhydrocarbons such as chloroform and carbon tetrachloride, ethers such astetrahydrofuran and 1,4-dioxane, and the like. Among these, methanol ispreferably used particularly when the compound of the formula (IV) ismethyl acrylate.

In this reaction, it is preferred to use the acrylic acid ester (IV) inan amount of from about twice by mole to a slight excess based on thealkylenediamine compound (III). More generally, the amount of theacrylic acid ester (IV) per mole of the alkylenediamine compound (III)is preferably in the range of from about 2 to about 4 moles, morepreferably in the range of from about 2.0 to about 2.5 moles. Usually,this reaction proceeds in the range of from about 20° C. to refluxingtemperature, but preferably it is carried out under reflux. Thisreaction usually proceeds under an atmospheric pressure, but it may becarried out under pressure.

In the method with Michael reaction, the acrylic acid ester (IV) reactswith the alkylenediamine compound (III) in relatively good efficiency togive the hindered piperidine compound (I) if R¹ in the formula (IV)representing the acrylic acid ester is a lower alkyl group of about thesame bulkiness as that of methyl, ethyl, propyl and, at most, butyl. Itwas found, however, that the yield of the hindered piperidine compound(I) lowers as R¹ in the formula (IV) becomes large in its stericbulkiness. The present inventors, therefore, have extensively studiedhow to produce the hindered piperidine compound of the formula (I)wherein R¹ is limited, among those defined hereinbefore, to anN-substituted or N-unsubstituted 2,2,6,6-tetramethyl-4-piperidyl group,an alkyl group having 3 or more carbon atoms or an arylalkyl group. As aresult, the present inventors have found a method giving an increasedyield.

That is, the desired hindered piperidine compound represented by theformula (I) wherein R¹ is an N-substituted or N-unsubstituted2,2,6,6-tetramethyl-4-piperidyl group, a C₃ -C₁₈ alkyl group which maycontain a cyclic portion, or a C₇ -C₁₈ arylalkyl group, can be producedby firstly synthesizing a compound of the formula (I) wherein R¹ ismethyl or ethyl, i.e. a lower alkyl ester represented by the formula(Ia), ##STR6## wherein R¹¹ is methyl or ethyl, and R² and n are asdefined above, by Michael reaction, if necessary, isolating andpurifying the resulting compound (Ia) by the known methods, and thensubjecting the isolated and purified product or the reaction mixture andan alcohol represented by the formula (V),

    R.sup.1 OH                                                 (V)

wherein R¹ is an N-substituted or N-unsubstituted2,2,6,6-tetramethyl-4-piperidyl group, a C₃ -C₁₈ alkyl group which maycontain a cyclic portion, or a C₇ -C₁₈ arylalkyl group, totransesterification.

This transesterification is carried out in the presence of atransesterification catalyst. Among the compounds of the formula (I)wherein R¹ is propyl or butyl are also those which can be produced inmoderate yields by Michael reaction, but transesterification is moreadvantageous.

In the lower alkyl ester of the formula (Ia) which is a material fortransesterification, a particularly preferred R¹¹ is methyl.Consequently, specific examples of the hindered piperidine compound ofthe formula (Ia) used in the transesterification include the following:

N,N'-bis(2-methoxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

N,N'-bis(2-methoxycarbonylethyl)-N,N'-bis(1,2,2,6,6-pentamethyl-4-piperidyl)-1,6-hexanediamine,

N,N'-bis(2-methoxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-1-octyloxy-4-piperidyl)-1,6-hexanediamineand the like.

Specific examples of the alcohol represented by the formula (V) include2,2,6,6-tetramethyl-4-piperidinol, 1,2,2,6,6-pentamethyl-4-piperidinol,2,2,6,6-tetramethyl-1-octyloxy-4-piperidinol,1-methoxy-2,2,6,6-tetramethyl-4-piperidinol, hexanol, octanol,2-ethyl-1-hexanol, octadecanol, benzyl alcohol and the like.

Specific examples of the transesterification catalyst include lithiumamide, sodium methoxide, potassium methoxide, lithium methoxide, tinoxide and the like.

Usually, it is preferred to carry out the transesterification of thelower alkyl ester of the formula (Ia) with the alcohol of the formula(V) in a solvent. The preferred solvent includes aromatic hydrocarbonssuch as benzene, toluene, xylene, cymene, monochlorobenzene ando-dichlorobenzene, ethers such as tetrahydrofuran and 1,4-dioxane, andthe like.

In this reaction, it is preferred to use the alcohol (V) in an amount offrom about twice by mole to a slight excess based on the lower alkylester (Ia). More generally speaking, the amount of the alcohol (V) permole of the lower alkyl ester (Ia) is preferably in the range of fromabout 2 to about 4 moles, more preferably in the range of from about 2.0to about 2.5 moles.

In this reaction, it is also preferred to use the transesterificationcatalyst in an amount ranging from about 0.02 to about 0.2 mole based onmole of the lower alkyl ester (Ia).

This transesterification usually proceeds in the range of from about 20°C. to refluxing temperature, but preferably it is carried out underreflux. Also, this reaction usually proceeds under an atmosphericpressure, but it may be carried out under reduced pressure or underpressure. Further, it is preferred to carry out this reaction whileremoving a low-boiling alcohol produced with the progress of thereaction out of the reaction system.

The compound of the formula (I) wherein R¹ is a hydroxyl group can beproduced by hydrolyzing a compound of the formula (I) wherein R¹ is alower alkyl group, for example, the lower alkyl ester represented by theformula (Ia).

After Michael reaction of the alkylenediamine compound of the formula(III) with the acrylic acid ester of the formula (IV) has come to anend, the desired hindered piperidine compound of the formula (I) can beisolated by removing the solvent used, or removing the solvent andcatalyst when transesterification or hydrolysis has been carried out asneed arises. If necessary, a purification operation may further beapplied by the known methods.

Any hindered piperidine compound in the scope of the formula (I) can beproduced by selecting proper materials and applying the above operation.

Further, if necessary, the groups R² in the formula (I) and/or R³ in theformula (II) can be modified by firstly producing the compound of theformula (I) wherein R¹ is alkyl or arylalkyl and R² is hydrogen, or thecompound of the formula (I) wherein R¹ is N-unsubstituted2,2,6,6-tetramethyl-4-piperidyl and R² is hydrogen, or the compound ofthe formula (I) wherein R¹ is 4-piperidyl represented by the formula(II) and either one of R² or R³ is hydrogen, and then treating theresulting compound according to the known methods, for example, methodsdisclosed in EP-A-319,480, U.S. Pat. No. 4,665,185 and particularlyExamples 14, 23, 38, 48 and 60 to 65 of EP-A-309,402.

For example, by treating the compound of the formula (I) wherein R¹ isalkyl or arylalkyl and R² is hydrogen with a mixture of formaldehyde andformic acid, R² can be methylated. Also, by treating the compound of theformula (I) wherein R¹ is N-unsubstituted2,2,6,6-tetramethyl-4-piperidyl and R² is hydrogen with a mixture offormaldehyde and formic acid, the N-position of the2,2,6,6-tetramethyl-4-piperidyl group and R² can be methylated at thesame time. Further, by reacting the compound of the formula (I) whereinR² is hydrogen, or the compound of the formula (I) wherein R¹ is4-piperidyl represented by the formula (II) and R³ is hydrogen with anoxidizing agent, e.g. hydroperoxide, and then reducing the resultingcompound, R² and/or R³ can be converted to a hydroxyl group. Stillfurther, by reacting the compound of the formula (I) wherein R² ishydrogen, or the compound of the formula (I) wherein R¹ is 4-piperidylrepresented by the formula (II) and R³ is hydrogen with an alkane orcycloalkane in the presence of an oxidizing agent, an alkyloxy orcycloalkyloxy group can be introduced into R² and/or R³.

Specific examples of the hindered piperidine compound of the formula (I)thus obtained include the following.

Compound A:N,N'-bis(2-methoxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

Compound B:N,N'-bis[2-(2,2,6,6-tetramethyl-4-piperidyloxycarbonyl)ethyl]-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

Compound C:N,N'-bis(2-carboxyethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

Compound D:N,N'-bis(2-ethoxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

Compound E:N,N'-bis(2-propoxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

Compound F:N,N'-bis(2-isopropoxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

Compound G:N,N'-bis(2-butoxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

Compound H:N,N'-bis(2-isobutoxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

Compound I:N,N'-bis(2-pentyloxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

Compound J:N,N'-bis(2-hexyloxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

Compound K:N,N'-bis(2-cyclohexyloxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

Compound L:N,N'-bis(2-octyloxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

Compound M:N,N'-bis[2-(2-ethylhexyloxycarbonyl)ethyl]-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

Compound N:N,N'-bis(2-dodecyloxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

Compound O:N,N'-bis(2-octadecyloxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

Compound P:N,N'-bis(2-benzyloxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

Compound Q:N,N'-bis(2-methoxycarbonylethyl)-N,N'-bis(1,2,2,6,6-pentamethyl-4-piperidyl)-1,6-hexanediamine,

Compound R:N,N'-bis(2-methoxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-1-octyloxy-4-piperidyl)-1,6-hexanediamine,

Compound S:N,N'-bis(2-methoxycarbonylethyl)-N,N'-bis(1-hydroxy-2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

Compound T:N,N'-bis[2-(1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyl)ethyl]-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine,

Compound U:N,N'-bis[2-(1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyl)ethyl]-N,N'-bis(1,2,2,6,6-pentamethyl-4-piperidyl)-1,6-hexanediamine,

Compound V:N,N'-bis[2-(2,2,6,6-tetramethyl-4-piperidyloxycarbonyl)ethyl]-N,N'-bis(1,2,2,6,6-pentamethyl-4-piperidyl)-1,6-hexanediamine,

Compound W:N,N'-bis[2-(2,2,6,6-tetramethyl-1-octyloxy-4-piperidyloxycarbonyl)ethyl]-N,N'-bis(2,2,6,6-tetramethyl-1-octyloxy-4-piperidyl)-1,6-hexanediamine,

Compound X:N,N'-bis[2-(2,2,6,6-tetramethyl-4-piperidyloxycarbonyl)ethyl]-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)ethylenediamine,

Compound Y:N,N'-bis(2-methoxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)ethylenediamine.

The hindered piperidine compound represented by the formula (I) isitself a white solid or colorless liquid. This compound is effective tostabilize various kinds of organic material, particularly organicmaterials having a property to deteriorate by the action of light. Also,this compound does not color the organic materials when added thereto.

The organic material which can be stabilized by the present inventionmay be any of those having a property to deteriorate by the action oflight, there being no special limitation to target organic materials.Specific examples of the material include the following syntheticresins, rubbers, paints, oils and the like. These materials can bestabilized alone or in mixture of two or more of them.

Polyethylene such as low-density polyethylene (LD-PE), high-densitypolyethylene (HD-PE), and linear low-density polyethylene (LLD-PE);

Polypropylene;

Methylpentene polymer;

EEA (ethylene/ethyl acrylate copolymer) resin;

EVA (ethylene/vinyl acetate copolymer) resin;

polystyrenes such as polystyrene, poly(p-methylstyrene), andpoly(α-methylstyrene);

AS (acrylonitrile/styrene copolymer) resin;

ABS (acrylonitrile/butadiene/styrene copolymer) resin;

AAS (special acrylic rubber/acrylonitrile/styrene copolymer) resin;

ACS (acrylonitrile/chlorinated polyethylene/styrene copolymer) resin;

Chlorine-containing polymers such as chlorinated polyethylene,polychloroprene, chlorinated rubber, polyvinyl chloride, andpolyvinylidene chloride;

Methacrylic resin;

Ethylene/vinyl alcohol copolymer resin;

Fluorocarbon resin;

Polyacetal;

Grafted polyphenylene ether resin and polyphenylene sulfide resin;

Polyurethane;

Polyamide;

Polyethylene terephthalate and polybutylene terephthalate;

Polycarbonate;

Polyacrylate;

Polysulfone, polyetherether ketone and polyether sulfone;

Aromatic polyester resin;

Epoxy resin;

Diallylphthalate prepolymer;

Silicone resin;

Unsaturated polyester resin;

Acryl-modified benzoguanamine resin;

Benzoguanamine/melamine resin;

Urea resin;

Polybutadiene;

1,2-Polybutadiene;

Polyisoprene;

Styrene/butadiene copolymer;

Butadiene/acrylonitrile copolymer;

Ethylene/propylene copolymer;

Silicone rubber;

Epichlorohydrin rubber;

Acrylic rubber;

Natural rubber;

Chlorinated rubber paint;

Polyester resin paint;

Urethane resin paint;

Epoxy resin paint;

Acrylic resin paint;

Vinyl resin paint;

Aminoalkyl resin paint;

Alkyd resin paint;

Nitrocellulose resin paint;

Oil paint;

Wax; and

Lubricant.

The hindered piperidine compound represented by the formula (I) isblended in a stabilizing amount with organic materials. The preferredamount of the compound varies also with the kind of target organicmaterials, but it is usually preferred to use the compound in the rangeof from about 0.01 to about 5 parts by weight based on 100 parts byweight of the organic material. More preferably, the hindered piperidinecompound represented by the formula (I) is used in the range of fromabout 0.02 to about 2 parts by weight based on 100 parts by weight ofthe organic material.

If necessary, other additives may further be incorporated into organicmaterial compositions obtained by blending the hindered piperidinecompound of the formula (I) according to the present invention. Otheradditives include, for example, phenolic antioxidants, sulfur-containingantioxidants, phosphorus-containing antioxidants, ultraviolet absorbers,hindered amine light stabilizers other than the compound of the formula(I), lubricants, plasticizers, flame retardants, nucleating agents,metal deactivators, antistatic agents, pigments, inorganic fillers andthe like. These additives and the hindered piperidine compound of theformula (I) may be blended with organic materials at the same time or atseparate steps.

In blending the organic materials with the hindered piperidine compoundof the formula (I) and, if necessary, optionally used other additives,all the known methods and apparatus for obtaining a homogeneous mixturemay be employed. For example, when the organic material is a solidpolymer, these compound and/or additives may be blended with the solidpolymer directly or in the form of a master batch. When the organicmaterial is a synthetic polymer, these compound and/or additives may beblended with the polymer by not only the method described above, butalso a method in which the solution or dispersion of these compoundand/or additives is blended with the solution of the polymer in thecourse of polymerization of the polymer or immediately after finish ofthe polymerization. When the organic material is a liquid such as oils,these compound and/or additives may directly be added to dissolve themin the liquid, or may be added in the form of a solution or dispersionin a liquid medium.

The present invention will be explained in more detail with reference tothe following examples, but it is not to be interpreted as being limitedthereto. All percents and parts in the examples are by weight unlessotherwise stated.

EXAMPLE 1 Production ofN,N'-bis(2-methoxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine(Compound A)

Eighty grams (0.20 mole) ofN,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine and 200 g ofmethanol were added to a 1-liter four-necked flask, and thehexanediamine was completely dissolved in the methanol. To the resultingsolution was added dropwise a solution of 35 g (0.41 mole) of methylacrylate in 100 g of methanol at room temperature. Thereafter, reactionwas continued for 12 hours under reflux. After the reaction finished,the solvent was removed by evaporation, and the residue obtained wasrecrystallized from hexane to obtain 98 g (0.17 mole) of the entitledCompound A as a white solid in a yield of 85%.

Mass analysis (FD-MS): m/z 566 (M)⁺ Elementary analysis (C₃₂ H₆₂ N₄ O₄):Found C 68.1%, H 10.9%, N 10.0% Calcd. C 67.8%, H 11.0%, N 9.9% m.p.50°-52° C. ¹ H-NMR (270 MHz, CDCl₃): δ1.04(dd, J=12.5 and 12.2 Hz, 4H);1.12(s, 12H); 1.19(s, 12H); 1.2-1.4(m, 4H); 1.4-1.5(m, 4H); 1.63(dd,J=12.5 and 2.9 Hz, 4H); 2.44(t, J=7.1 Hz, 4H); 2.44(t, J=7.2 Hz, 4H);2.78(t, J=7.2 Hz, 4H); 2.97(tt, J=12.2 and 2.9 Hz, 2H); 3.67(s, 6H) ppm.

EXAMPLE 2 production ofN,N'-bis(2-ethoxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine(Compound D)

procedure was carried out according to Example 1 except that methylacrylate was replaced by the equimolar amount of ethyl acrylate, toobtain Compound D in a yield of 91%.

Mass analysis (FD-MS): m/z 594 (M)⁺ Elementary analysis (C₃₄ H₆₆ N₄ O₄):Found C 68.7%, H 10.9%, N 9.6% Calcd. C 68.6%, H 11.1%, N 9.4% m.p.58°-60° C. ¹ H-NMR (270 MHz, CDCl₃): δ1.04(dd, J=12.5 and 12.2 Hz, 4H);1.12(s, 12H); 1.19(s, 12H); 1.2-1.4(m, 4H); 1.26(t, J=7.3 Hz, 6H);1.4-1.5(m, 4H); 1.62(dd, J=12.5 and 2.9 Hz, 4H); 2.42(t, J=7.1 Hz, 4H);2.43(t, J=7.1 Hz, 4H); 2.78(t, J=7.1 Hz, 4H); 2.98(tt, J=12.2 and 2.9Hz, 2H); 4.13(q, J=7.3 Hz, 4H) ppm.

EXAMPLE 3 Production ofN,N'-bis(2-octadecyloxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine(Compound O)

To a four-necked flask equipped with a stirrer and a reflux condenserwere added 20.0 g (35 mmoles) ofN,N'-bis(2-methoxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine(Compound A) obtained in Example 1, 21.0 g (77 mmoles) of stearylalcohol and 200 ml of toluene, and the resulting mixture was stirredunder reflux. To the reaction mixture was added dropwise a solution of0.1 g (4 mmoles) of lithium amide in 3 g of methanol. Thereafter, thesolvent was distilled off while adding toluene, to complete thereaction. After the reaction was continued for 4 hours, toluene wasadded, and the reaction mixture was cooled to room temperature. Theorganic layer was washed three times with water and concentrated toobtain 23 g (22 mmoles) of Compound O in a yield of 63%. The yield ofCompound O based onN,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine wascalculated as 54%.

Mass analysis (FD-MS): m/z 1043 (M+1)⁺ Elementary analysis (C₆₆ H₁₃₀ N₄O₄): Found C 75.9%, H 13.0%, N 5.0% Calcd. C 76.0%, H 12.6%, N 5.4% m.p.45°-46° C. ¹ H-NMR (270 MHz, CDCl₃): δ0.88(t, J=6.6 Hz, 6H); 1.0-1.5(m,68H); 1.04(dd, J=12.3 and 12.2 Hz, 4H); 1.12(s, 12H); 1.19(s, 12H);1.6-1.7(m, 4H); 1.63(dd, J=12.2 and 2.6 Hz, 4H); 2.42(t, J=7.1 Hz, 8H);2.78(t, J=7.1 Hz, 4H); 2.97(tt, J=12.3 and 2.6 Hz, 2H); 4.05(t, J=6.7Hz, 4H) ppm.

EXAMPLE 4 (for comparison) Production ofN,N'-bis(2-octadecyloxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine(Compound O) by Michael reaction

To a 1-liter four-necked flask were added 20 g (50 mmoles) ofN,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine and 200 g ofmethanol, and the hexanediamine was completely dissolved in themethanol. To the resulting solution was added dropwise a solution of32.4 g (0.1 mole) of octadecyl acrylate in 100 g of methanol at roomtemperature, after which reaction was continued for 12 hours underreflux. The solvent was removed by evaporation, and FD-MS measurementwas carried out. As a result, it was found thatN-(2-octadecyloxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediaminewas produced in a small amount, but Compound O was not confirmed.

EXAMPLES 5 TO 16

Production of other compounds by transesterification

Procedure was carried out according to Example 3 except using varyingalcohols as a material, to obtain the compounds shown in Table 1 in therespective yields. The yields described here are based on Compound A.

                  TABLE 1                                                         ______________________________________                                         ##STR7##                                                                     Example                                                                       No.     Compound    R.sup.1        Yield                                      ______________________________________                                         5      B           2,2,6,6-Tetramethyl-4-                                                                       80%                                                            piperidyl                                                  6      E           n-Propyl       75%                                         7      F           Isopropyl      82%                                         8      G           n-Butyl        77%                                         9      H           Isobutyl       79%                                        10      I           n-Pentyl       54%                                        11      J           n-Hexyl        89%                                        12      K           Cyclohexyl     84%                                        13      L           n-Octyl        92%                                        14      M           2-Ethylhexyl   92%                                        15      N           n-Dodecyl      77%                                        16      P           Benzyl         81%                                        ______________________________________                                    

Compound B:

Mass analysis (FD-MS): m/z 816 (M)⁺ Elementary analysis (C₄₈ H₉₂ N₆ O₄):Found C 70.3%, H 11.4%, N 10.0% Calcd. C 70.5%, H 11.3%, N 10.3% ¹ H-NMR(270 MHz, CDCl₃): δ1.05(dd, J=12.3 and 12.2 Hz, 4H); 1.13(s, 12H);1.16(s, 12H); 1.19(s, 12H); 1.23(s, 12H); 1.1-1.5(m, 12H); 1.63(dd,J=12.3 and 2.7 Hz, 4H); 1.93(dd, J=12.5 and 4.2 Hz, 4H); 2.40(t, J=7.4Hz, 4H); 2.43(t, J=7.6 Hz, 4H); 2.78(t, J=7.4 Hz, 4H); 2.98(tt, J=12.2and 2.7 Hz, 2H); 5.20(tt, J=11.4 and 4.2 Hz, 2H) ppm.

Compound E:

Mass analysis (FD-MS): m/z 622 (M)⁺ Elementary analysis (C₃₆ H₇₀ N₄ O₄):Found C 69.5%, H 11.1%, N 9.0% Calcd. C 69.4%, H 11.3%, N 9.0% m.p.43°-44° C. ¹ H-NMR (270 MHz, CDCl₃): δ6 0.95(t, J=7.0 Hz, 6H); 1.04(dd,J=12.5 and 12.2 Hz, 4H); 1.12(s, 12H); 1.19(s, 12H); 1.2-1.3(m, 4H);1.4-1.5(m, 4H); 1.63(dd, J=12.5 and 3.0 Hz, 4H); 1.6-1.7(m, 4H); 2.43(t,J=7.3 Hz, 8H); 2.78(t, J=7.3 Hz, 4H); 2.98(tt, J=12.2 and 3.0 Hz, 2H);4.03(t, J=7.0 Hz, 4H) ppm.

Compound F:

Mass analysis (FD-MS): m/z 622 (M)⁺ Elementary analysis (C₃₆ H₇₀ N₄ O₄):Found C 69.2%, H 11.1%, N 9.4% Calcd. C 69.4%, h 11.3%, N 9.0% ¹ H-NMR(270 MHz, CDCl₃): δ1.04(dd, J=12.5 and 12.2 Hz, 4H); 1.12(s, 12H);1.19(s, 12H); 1.2-1.3(m, 4H); 1.24(d, J=6.3 Hz, 12H); 1.4-1.5(m, 4H);1.63(dd, J=12.5 and 3.0 Hz, 4H); 2.39(t, J=7.0 Hz, 4H); 2.42(t, J=7.3Hz, 4H); 2.77(t, J=7.3 Hz, 4H); 2.98(tt, J=12.2 and 3.0 Hz, 2H);5.00(hept, J=6.3 Hz, 2H) ppm.

Compound G:

Mass analysis (FD-MS): m/z 650 (M)⁺ Elementary analysis (C₃₈ H₇₄ N₄ O₄):Found C 70.2%, H 11.2%, N 8.7% Calcd. C 70.1%, H 11.5%, N 8.6% m.p.66°-67° C. ¹ H-NMR (270 MHz, CDCl₃): δ0.94(t, J=7.3 Hz, 6H); 0.9-1.1(m,4H); 1.12(s, 12H); 1.19(s, 12H); 1.2-1.3(m, 4H); 1.3-1.5(m, 8H);1.6-1.7(m, 8H); 2.42(t, J=7.3 Hz, 8H); 2.78(t, J=7.3 Hz, 4H); 2.97(tt,J=12.2 and 3.1 Hz, 2H); 4.07(t, J=6.6 Hz, 4H) ppm.

Compound H:

Mass analysis (FD-MS): m/z 650 (M)⁺ Elementary analysis (C₃₈ H₇₄ N₄ O₄):Found C 70.2%, H 12.0%, N 8.6% Calcd. C 70.1%, H 11.5%, N 8.6% m.p.72°-73° C. ¹ H-NMR (270 MHz, CDCl₃): δ0.94(d, J=6.6 Hz, 12H); 1.04(dd,J=12.5 and 12.2 Hz, 4H); 1.12(s, 12H); 1.19(s, 12H); 1.2-1.3(m, 4H);1.4-1.5(m, 4H); 1.63(dd, J=12.5 and 3.0 Hz, 4H); 1.8-2.0(m, 2H); 2.44(t,J=7.3 Hz, 8H); 2.79(t, J=7.3 Hz, 4H); 2.98(tt, J=12.2 and 3.0 Hz, 2H);3.86(d, J=6.6 Hz, 4H) ppm.

Compound I:

Mass analysis (FD-MS): m/z 678 (M)⁺ Elementary analysis (C₄₀ H₇₈ N₄ O₄):Found C 70.7%, H 11.8%, N 8.3% Calcd. C 70.8%, H 11.6%, N 8.3% m.p.36°-37° C. ¹ H-NMR (270 MHz, CDCl₃): δ0.91(t, J=7.1 Hz, 6H); 0.9-1.1(m,4H); 1.12(s, 12H); 1.19(s, 12H); 1.2-1.5(m, 16H); 1.6-1.7(m, 8H);2.42(t, J=7.2 Hz, 8H); 2.78(t, J=7.2 Hz, 4H); 2.97(tt, J=12.4 and 3.1Hz, 2H); 4.06(t, J=6.9 Hz, 4H ) ppm.

Compound J:

Mass analysis (FD-MS): m/z 706 (M)⁺ Elementary analysis (C₄₂ H₈₂ N₄ O₄):Found C 71.4%, H 12.0%, N 8.1% Calcd. C 71.3%, H 11.7%, N 8.0% ¹ H-NMR(270 MHz, CDCl₃): δ0.89(t, J=6.8 Hz, 6H); 0.9-1.1(m, 4H); 1.12(s, 12H);1.19(s, 12H); 1.2-1.5(m, 20H); 1.6-1.7(m, 8H); 2.42(t, J=7.2 Hz, 8H);2.78(t, J=7.2 Hz, 4H); 2.97(tt, J=12.2 and 3.0 Hz, 2H); 4.06(t, J=6.8Hz,4H) ppm.

Compound K:

Mass analysis (FD-MS): m/z 704 (M)⁺ Elementary analysis (C₄₂ H₇₈ N₄ O₄):Found C 71.6%, H 11.4%, N 8.4% Calcd. C 71.8%, H 11.2%, N 8.0% ¹ H-NMR(270 MHz, CDCl₃): δ1.04(dd, J=12.5 and 12.2 Hz, 4H); 1.12(s, 12H);1.19(s, 12H); 1.2-2.0(m, 28H); 1.63(dd, J=12.5 and 3.0 Hz, 4H); 2.40(t,J=7.3 Hz, 4H); 2.43(t, J=6.3 Hz, 4H); 2.78(t, J=7.3 Hz, 4H); 2.98(tt,J=12.2 and 3.0 Hz, 2H); 4.7-4.8(m, 2H) ppm.

Compound L:

Mass analysis (FD-MS): m/z 762 (M)⁺ Elementary analysis (C₄₆ H₉₀ N₄ O₄):Found C 72.1%, H 12.4%, N 7.5% Calcd. C 72.4%, H 11.9%, N 7.4% ¹ H-NMR(270 MHz, CDCl₃): δ0.88(t, J=6.8 Hz, 6H); 1.04(dd, J=12.5 and 12.2 Hz,4H); 1.12(s, 12H); 1.19(s, 12H); 1.2-1.5(m, 28H); 1.6-1.7(m, 4H);1.63(dd, J=12.5 and 2.6 Hz, 4H); 2.42(t, J=7.2 Hz, 8H); 2.78(t, J=7.2Hz, 4H); 2.97(tt, J=12.2 and 2.6 Hz, 2H); 4.06(t, J=6.8 Hz, 4H) ppm.

Compound M:

Mass analysis (FD-MS): m/z 763 (M+1)⁺ Elementary analysis (C₄₆ H₉₀ N₄O₄): Found C 72.4%, H 11.5%, N 7.8% Calcd. C 72.4%, H 11.9%, N 7.4% ¹H-NMR (270 MHz, CDCl₃): δ0.89(t, J=7.4 Hz, 12H); 1.04(dd, J=12.9 and12.1 Hz, 4H); 1.12(s, 12H); 1.19(s, 12H); 1.2-1.5(m, 24H); 1.5-1.7(m,2H); 1.63(dd, J=12.9 and 3.0 Hz, 4H); 2.43(t, J=7.3 Hz, 8H); 2.79(t,J=7.3 Hz, 4H); 2,97(tt, J=12.1 and 3.0 Hz, 2H); 3.98(dd, J=5.8 and 1.2Hz, 4H) ppm.

Compound N:

Mass analysis (FD-MS): m/z 874 (M)⁺ Elementary analysis (C₅₄ H₁₀₆ N₄O₄): Found C 74.0%, H 12.7%, N 6.0% Calcd. C 74.1%, H 12.2%, N 6.4% ¹H-NMR (270 MHz, CDCl₃): δ0.88(t, J=6.8 Hz, 6H); 1.04(dd, J=12.3 and 12.2Hz, 4H); 1.12(s, 12H); 1.19(s, 12H); 1.2-1.5(m, 40H); 1.6-1.7(m, 8H);1.63(dd, J=12.2 and 2.5 Hz, 4H); 2.42(t, J=7.2 Hz, 8H); 2.78(t, J=7.2Hz, 4H); 2.97(tt, J=12.3 and 2.5 Hz, 2H); 4.05(t, J=6.8 Hz, 4H) ppm.

Compound P:

Mass analysis (FD-MS): m/z 718 (M)⁺ Elementary analysis (C₄₄ H₇₀ N₄ O₄):Found C 73.3%, H 10.3%, N 7.7% Calcd. C 73.5%, H 9.8%, N 7.8% ¹ H-NMR(270 MHz, CDCl₃): δ1.02(dd, J=12.5 and 12.0 Hz, 4H); 1.10(s, 12H);1.16(s, 12H); 1.3-1.4(m, 4H); 1.4-1.6(m, 4H); 1.60(dd, J=12.5 and 3.0Hz, 4H); 2.42(t, J=7.3 Hz, 4H); 2.48(t, J=7.3 Hz, 4H); 2.80(t, J=7.3 Hz,4H); 2.96(tt, J=12.0 and 3.0 Hz, 2H); 5.11(s, 4H); 7.3-7.5(m, 10H) ppm.

EXAMPLE 17 (for comparison) Production ofN,N'-bis(2-n-butoxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine(Compound G)

Procedure was carried out according to Example 4 except that octadecylacrylate was replaced by the equimolar amount of n-butyl acrylate, toobtain Compound G in a yield of 53%.

EXAMPLE 18 Production ofN,N'-bis(2-methoxycarbonylethyl)-N,N'-bis(1,2,2,6,6-pentamethyl-4-piperidyl)-1,6-hexanediamine(Compound Q)

To a four-necked flask equipped with a stirrer and a reflux condenserwere added 3.7 g (41 mmoles) of a 37% aqueous formaldehyde solution, 100ml of toluene and 1.9 g (41 mmoles) of formic acid. To the resultingmixture was added dropwise a solution of 10 g (17 mmoles) ofN,N'-bis(2-methoxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine(Compound A) obtained in Example 1 in 50 ml of toluene. Thereafter, theresulting mixture was refluxed for 3 hours. After the reaction finished,a 5% aqueous sodium hydroxide solution was added to separate thereaction mixture into two layers. The organic layer of the two layerswas washed three times with water. The solvent was removed byevaporation to obtain 9 g (15 mmoles) of Compound Q as a viscous liquidin a yield of 88%.

Mass analysis (FD-MS): m/z 594 (M)⁺ Elementary analysis (C₃₄ H₆₆ N₄ O₄):Found C 69.7%, H 11.1%, N 10.2% Calcd. C 68.6%, H 11.2%, N 9.4% ¹ H-NMR(270 MHz, CDCl₃): δ1.00(s, 12H); 1.14(s, 12H); 1.1-1.6(m, 16H); 2.22(s,6H); 2.42(t, J=7.0 Hz, 4H); 2.43(t, J=7.0 Hz, 4H); 2.78(t, J=7.0 Hz,4H); 2.8-2.9(m, 2H); 3.66(s, 6H) ppm.

EXAMPLE 19 Production ofN,N'-bis(2-carboxyethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine(Compound C)

To a four-necked flask equipped with a stirrer and a reflux condenserwere added 26.3 g (46 mmoles) ofN,N'-bis(2-methoxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine(Compound A) obtained in Example 1 and 100 g of water. The resultingmixture was stirred at room temperature. After dissolution of Compound Awas confirmed, 100 ml of hexane was added to separate the reactionmixture into two layers. The aqueous layer of the two layers wasisolated and concentrated to obtain 23 g (43 mmoles) of Compound C in ayield of 92%.

Mass analysis (FD-MS): m/z 538 (M)⁺ m.p.: >250° C. Elementary analysis(C₃₀ H₅₈ N₄ O₄): Found C 66.4%, H 10.9%, N 10.2% Calcd. C 66.9%, H10.9%, N 10.4% ¹ H-NMR (270 MHz, D₂ O): δ1.3-1.5(m, 4H); 1.37(s, 12H);1.43(s, 12H); 1.5-1.7(m, 8H), 1.9-2.1(m, 4H); 2.44(t, J=7.6 Hz, 4H);2.72(t, J=7.8 Hz, 4H); 2.97(t, J=7.6 Hz, 4H); 3.3-3.4(m, 2H) ppm.

EXAMPLE 20 Production ofN,N'-bis(2-methoxycarbonylethyl)-N,N'-bis(1-hydroxy-2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine(Compound S)

To a four-necked flask equipped with a stirrer and a reflux condenserwere added 20.0 g (35 mmoles) ofN,N'-bis(2-methoxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine(Compound A) obtained in Example 1, 0.2 g (0.75 mmole) of molybdenumhexacarbonyl and 200 ml of dichloroethane. The resulting mixture wasstirred at 60° C. To the reaction mixture was then slowly added dropwise28 g (248 mmoles) of tert-butyl hydroperoxide, after which reaction wascontinued for 8 hours under reflux. Inorganic matters were removed byfiltration, and the filtrate was washed with a 5% aqueous sodium sulfitesolution. The solvent was concentrated, and the product obtained waspurified by column chromatography on silica gel (eluent, hexane:ethylacetate=2:1). Further, the purified product obtained here was added toan autoclave together with 100 ml of dry tetrahydrofuran, 5 g ofmagnesium sulfate and 2 g of 5% palladium on carbon, and the mixture wasstirred at room temperature for 16 hours under a hydrogen pressure of 10atm. After the solid matter was removed by filtration, the solvent wasconcentrated, and the product was purified by column chromatography onsilica gel (eluent, hexane:ethyl acetate=1:1) to obtain 6 g (10 mmoles)of Compound S in a yield of 28%.

Mass analysis (FD-MS): m/z 598 (M)⁺ Elementary analysis (C₃₂ H₆₂ N₄ O₆):Found C 64.5%, H 10.4%, N 9.6% Calcd. C 64.2%, H 10.4%, N 9.4%

EXAMPLE 21

Weather resistance test of polypropylene Blending:

    ______________________________________                                        Unstabilized polypropylene                                                                           100    parts                                           Calcium stearate       0.05   part                                            Test Compound          0.1    part                                            ______________________________________                                    

The above blend was melt-kneaded at 230° C. on a 30 mmφ single-screwextruder and pelletized. This pellet was formed into a sheet of 1 mm inthickness at 230° C. on an injection molding machine. This sheet wasused as a test piece. This test piece was put in a sunshineweather-O-meter having a light source of carbon arc and irradiated withlight under conditions of a black panel temperature being 83° C. and nowater spraying. The weather resistance was evaluated by a time which hadpassed until cracks appeared on the irradiated surface of the testpiece. The results are shown in Table 2.

                  TABLE 2                                                         ______________________________________                                                  Test compound                                                                             Weather resistance                                      ______________________________________                                        Present invention                                                                         Compound A    780 hours                                           Comparison  None          120 hours                                           ______________________________________                                    

EXAMPLE 22

Weather resistance test of polypropylene Blending:

    ______________________________________                                        Unstabilized propylene/ethylene                                                                        100 parts                                            block copolymer*.sup.1                                                        Calcium stearate         0.05 part.sup.                                       Phenolic antioxidant*.sup.2                                                                            0.1 part.sup.                                        Phosphorus-containing antioxidant*.sup.3                                                               0.05 part.sup.                                       Test compound            0.2 part.sup.                                        ______________________________________                                         *.sup.1 Ethylene content of 7.3%                                              *.sup.2                                                                       3,9-Bis[2-{3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dim    thylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane                                 *.sup.3 Bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite         

The above blend was melt-kneaded at 230° C. on a 30 mmφ single-screwextruder and pelletized. This pellet was formed into a sheet of 1 mm inthickness at 230° C. on an injection molding machine. This sheet wasused as a test piece. This test piece was put in a sunshineweather-O-meter having a light source of carbon arc and irradiated withlight under conditions of a black panel temperature being 83° C. and awater spray cycle being 12 minutes/60 minutes. The weather resistancewas evaluated by a time which had passed until cracks appeared on theirradiated surface of the test piece. The results are shown in Table 3.

                  TABLE 3                                                         ______________________________________                                         ##STR8##                                                                                              Life until                                                                    cracks                                               Run   Sym-     Compound            appear                                     No.   bol      R.sup.1         R.sup.2                                                                             (hour)                                   ______________________________________                                         1    A        Methyl          H     660                                       2    B        2,2,6,6-Tetramethyl-4-                                                                        H     960                                                     piperidyl                                                       3    Q        Methyl          Methyl                                                                              660                                       4    C        H               H     600                                       5    D        Ethyl           H     660                                       6    E        n-Propyl        H     660                                       7    F        Isopropyl       H     660                                       8    G        n-Butyl         H     660                                       9    H        Isobutyl        H     660                                      10    I        n-Pentyl        H     660                                      11    J        n-Hexyl         H     660                                      12    K        Cyclohexyl      H     660                                      13    L        n-Octyl         H     660                                      14    M        2-Ethylhexyl    H     660                                      15    N        n-Dodecyl       H     660                                      16    O        n-Octadecyl     H     600                                      17    P        Benzyl          H     600                                      18    None                     120                                            ______________________________________                                    

The hindered piperidine compound of the present invention givesexcellent properties as a stabilizer, particularly as a lightstabilizer, to various organic materials including thermoplastic resinssuch as polyolefin. For example, a resin containing this piperidinecompound is stable against photo-oxidation in practical use, and alsobrings about no color change due to the blending of the compound. Thus,molded products of high quality can be obtained from such a resin.

What is claimed is:
 1. A stabilized organic material composition,comprising an organic material and a hindered piperidine compoundrepresented by the formula (I), ##STR9## wherein R¹ is a2,2,6,6-tetramethyl-4-piperidyl group, a hydrogen atom, a C₁ -C₁₈ alkylgroup, or a C₇ -C₁₈ arylalkyl group; R² is a hydrogen atom, a C₁ -C₁₀alkyl group, a C₁ -C₁₈ alkyloxy group, or a hydroxyl group; and n is aninteger of 2 to
 8. 2. A composition according to claim 2, wherein R¹ isa 2,2,6,6-tetramethyl-4-piperidyl group.
 3. A composition according toclaim 2, wherein the N-position of the 2,2,6,6-tetramethyl-4-piperidylgroup has a substituent selected from the group consisting of a C₁ -C₁₀alkyl group, a C₁ -C₁₈ alkoxy group and a hydroxyl group.
 4. Acomposition according to claim 3, wherein the N-position of the2,2,6,6-tetramethyl-4-piperidyl group has a substituent selected fromthe group consisting of a C₁ -C₃ alkyl group, an octyloxy group and acyclohexyloxy group.
 5. A composition according to claim 2, wherein R¹is a methyl group.
 6. A composition according to claim 2, wherein R² isselected from the group consisting of hydrogen, a C₁ -C₃ alkyl group, anoctyloxy group, a cyclohexyloxy group and a hydroxyl group.
 7. Acomposition according to claim 2, wherein n is
 6. 8. A compositionaccording to claim 2, wherein R¹ is selected from the group consistingof a methyl group, an N-unsubstituted 2,2,6,6-tetramethyl-4-piperidylgroup, a 1,2,2,6,6-pentamethyl-4-piperidyl group, a2,2,6,6-tetramethyl-1-octyloxy-4-piperidyl group and a1-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidyl group, R² is selectedfrom the group consisting of a hydrogen atom, a C₁ -C₃ alkyl group, anoctyloxy group, a cyclohexyloxy group and a hydroxyl group, and n is 6.9. A composition according to claim 2, wherein the organic material isselected from the group consisting of synthetic resins, rubbers, paintsand oils.
 10. A composition according to claim 2, wherein the hinderedpiperidine compound is present in an amount of from about 0.01 to about5 parts by weight based on 100 parts by weight of the organic material.11. A composition according to claim 3, wherein the substituent on theN-position of the 2,2,6,6-tetramethyl-4-piperidyl group is a C₁ -C₁₀alkyl group.
 12. A composition according to claim 3, wherein thesubstituent on the N-position of the 2,2,6,6-tetramethyl-4-piperidylgroup is a C₁ -C₁₈ alkoxy group.
 13. A composition according to claim 1,wherein R¹ is a C₁ -C₁₈ alkyl group.
 14. A composition according toclaim 1, wherein R² is a C₁ -C₁₀ alkyl group.
 15. A compositionaccording to claim 1, wherein R² is a C₁ -C₁₈ alkyloxy group.
 16. Acomposition according to claim 10, wherein the hindered piperidinecompound is present in an amount of from about 0.02 to about 2 parts byweight based on 100 parts by weight of the organic material.
 17. Acomposition according to claim 11, wherein the C₁ -C₁₀ alkyl groupsubstituent on the N-position of the 2,2,6,6-tetramethyl-4-piperidylgroup contains a cyclic alkyl group located at a middle or terminalposition of the C₁ -C₁₀ alkyl group, the cyclic alkyl group being bondedto the N-position through one or two --CH₂ -- groups.
 18. A compositionaccording to claim 11, wherein the C₁ -C₁₀ alkyl group substituent onthe N-position of the 2,2,6,6-tetramethyl-4-piperidyl group is acyclohexylmethyl group or a cyclohexylethyl group.
 19. A compositionaccording to claim 12, wherein the C₁ -C₁₈ alkoxy group substituent onthe N-position of the 2,2,6,6-tetramethyl-4-piperidyl group is a cyclicalkoxy group.
 20. A composition according to claim 12, wherein the C₁-C₁₈ alkoxy group substituent on the N-position of the2,2,6,6-tetramethyl-4-piperidyl group is a cyclohexyloxy group.
 21. Acomposition according to claim 13, wherein the C₁ -C₁₈ alkyl group is acyclic alkyl group.
 22. A composition according to claim 21, wherein thecyclic alkyl group is a cyclohexyl group.
 23. A composition according toclaim 14, wherein the C₁ -C₁₀ alkyl group contains a cyclic alkyl grouplocated at a middle or terminal portion of the C₁ -C₁₀ alkyl group, thecyclic alkyl group being bonded to the hindered piperidine compoundthrough one or two --CH₂ -- groups.
 24. A composition according to claim14, wherein the C₁ -C₁₀ alkyl group is a cyclohexylmethyl group or acyclohexylethyl group.
 25. A composition according to claim 15, whereinthe C₁ -C₁₈ alkyloxy group is a cyclic alkoxy group.
 26. A compositionaccording to claim 15, wherein the C₁ -C₁₈ alkyloxy group is acyclohexyloxy group.
 27. A composition according to claim 1, wherein theC₇ -C₁₈ arylalkyl group is a benzyl group or a phenethyl group.
 28. Acomposition according to claim 1, wherein the hindered piperidinecompound isN,N'-bis(2-methoxycarbonylethyl)-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine.29. A composition according to claim 1, wherein the hindered piperidinecompound isN,N'-bis[2-(2,2,6,6-tetramethyl-4-piperidyloxycarbonyl)ethyl]-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)-1,6-hexanediamine.30. A composition according to claim 1, wherein the hindered piperidinecompound isN,N'-bis(2-methoxycarbonylethyl)-N,N'-bis(1,2,2,6,6-pentamethyl-4-piperidyl)-1,6-hexanediamine.31. A composition according to claim 1, wherein R¹ is selected from thegroup consisting of 2,2,6,6-tetramethyl-4-piperidyl,1,2,2,6,6-pentamethyl-4-piperidyl,2,2,6,6-tetramethyl-1-octyloxy-4-piperidyl,1-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidyl,1-hydroxy-2,2,6,6-tetramethyl-4-piperidyl, hydrogen, methyl, ethyl and2-ethylhexyl.
 32. A composition according to claim 1, wherein R¹ isselected from the group consisting of 2,2,6,6-tetramethyl-4-piperidyl,1,2,2,6,6-pentamethyl-4-piperidyl,2,2,6,6-tetramethyl-1-octyloxy-4-piperidyl,1-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidyl,1-hydroxy-2,2,6,6-tetramethyl-4-piperidyl, hydrogen, methyl, ethyl and2-ethylhexyl, R² is selected from the group consisting of a hydrogenatom, a C₁ -C₃ alkyl group, an octyloxy group, a cyclohexyloxy group anda hydroxyl group, and n is
 6. 33. A composition according to claim 1,wherein R₁ is a methyl group or a 2,2,6,6-tetramethyl-4-piperidyl group.34. A composition according to claim 1, wherein R₂ is a hydrogen atom ora methyl group.
 35. A composition according to claim 7, wherein R₁ is amethyl group or a 2,2,6,6-tetramethyl-4-piperidyl group and R₂ is ahydrogen atom or a methyl group.